The primary purpose of the proposed work is to define and characterize that neurogenic activation of the adenohypophysis which is directly related to the acute release of gonadotropic hormones (LH, FSH and prolactin) which causes ovulation and corpus luteum formation. Initially, attention will be focused on analysis of neural and endocrine events in unanesthetized, unrestrained, female rats. The complex electroencephalographic (EEG) and/or multiple unit activities (MUA) of the septal, preoptic and hypothalamic brain will be subjected to computer analysis to detect neural events which are consistently related to release of gonadotropin, as measured concurrently by radioimmunoassay of sequential blood samples from individual animals. In addition, the influence of certain factors (such as hormonal feedback, environmental changes, etc.) which are thought to "set the stage" for neurogenic activation in the intact rat will be studied separately or in combination. Subsequently, studies will be done to see whether, or how, these neurogenic events are modified by drugs which can modify the endocrine events (i.e., contraceptive steroids, clomiphene, etc.).